Control signal generating device moving sound speaker systems including a plurality of speakers and a

ABSTRACT

A multi-speaker system where the sound emanating from the speakers is sequentially amplified by means of electronic control circuits to give the impression of sound movement around the listener.

Muted States Patent 1191 1111 3,757,046 Williams Sept. 4, 1973 MOVING SOUND SPEAKER SYSTEM 2,313,867 3 1943 Garity 179/100.3

INCLUDING A PLURALITY F SPEAKERS 2,298,618 g w AND A CoNTRoL SIGNAL GENERATING Z13 fi s; DEVICE 3,156,770 11/1964 Trainor 76 Inventor; Thomas H. Williams, 2015 Country 2,941,044 6/1960 Volkmann 179/1 G Squire Dr., Urbana, 111. 61801 [22] Filed: July 23, 1970 Primary Examiner-Kathleen H. Claffy Assistant Examiner-Thomas DAmico [21] Appl' 57445 AttorneyShlesinger, Arkwright & Garvey [52] U.S. Cl 179/1 G, 179/1 60, 84/124,

84/DIG- 1 57 ABSTRACT [51] Int. Cl. .1 H04r 5/00 1 [58] Field of Search 179/16, 1 AT, 16 P, A mu|ti speaker system where the sound emanating 1 G0; 27 from the speakers is sequentially amplified by means of electronic control circuits to give the impression of I 56] References C'ted sound movement around the listener.

UNITED STATES PATENTS 3,008,011 11/1961 Fine 179/1 G 17 Claims, 11 Drawing Figures R CHANNEL A TERMINAL M LP LUL Z E 1 l 84AMPL|FIER 1 52 74 l' l 1 X 1 17 w 4 e d 1 X -1 SPEAKER 1 L. 5 4 9 4 X 90, I 3 J 1 9 e I 1 a 8 2 1 1 A CHANNEL B 1 I r so I 1 {T 62 l v\ 0 6 4 X 114 SIGNAL GENERATOR PATENTEBSEP 41m saw u 0F 5 Fig. 9

1 NVENT OR. Thomas H. Wf/l/ams ATTORNEYS SUMMARY OF THE INVENTION This invention broadens the possibility of a special sound presentation to an audience by providing a system which presents an impression of controlled movement of the sound relative to the listener. The sound industry has strived for a more versatile presentation to an audience, either in the home or theater, where a sound program duplicates as closely as possible the actual sound the listener would hear were he physically present at the scene hearing a live presentation.

Also special effects can be created with a nonaccurate sound presentation where the sound source could move, stop, and reverse with respect to the listener.

It makes possible a more accurate spatial high fidelity reproduction in a multi-speaker system wherein an impression of relative motion of the listener with respect to the sound is to be created as part of a presentation.

The demand for a more diversifiedsound presentation has been growing with increased sophistication of the sound industry.

With this invention it is possible to create the illusion of either movement of the sound about the audience, or movement of the audience with respect to a sound source in a multi-speaker system. A high degree of accuracy and flexibility in producing relative movement between the listener and the sound presentation is brought about by the use of special control circuitry which coordinates the audio signal outputfrom each speaker to accurately convey. an impression of movement of sound, such as movement of a vehicle about the listener. I

Such sound effects are produced in this invention by the use of special amplitude control signal circuits for each speaker audio signal, which vary in amplitude, frequency and displacement with respect to corresponding signals supplied to other speakers of the system so as to control the audio signal output of each of the speakers to bring about the desired overall sound effect.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of a room having a plurality of speakers disposed therein;

FIG. 2A is an amplitude time-diagram showing the amplitude control waves for the speakers of FIG. 1;

FIG. 2B is an amplitude time-diagram for pulse control waves that can be used in conjunction with the speakers of FIG. 1;

FIG. 3 is a block diagram showing a two-channel audio source and a control or rotating sound circuit in dotted outline as connected to the speakers of FIG. 1;

FIGS. 4 and 5 are block diagrams of the circuits used to generate the amplitude control waves of FIG. 2A;

FIG. 6 is a schematic circuit illustrating in detail the amplitude control wave circuit of FIG. 4;

FIG. 7 is an amplitude time-diagram generated by the circuit of FIG. 6 for the master and inverted master amplitude control signals;

FIG. 8 is a multiplier circuit as used in the'block diagram of FIG. 3;

FIG. 9 shows a schematic for the adder circuit used in the block diagram of FIG. 3; and

FIG. 10 is a block diagram for an amplitude control wave circuit using a unijunction as a clock circuit, and a shift register circuit for generating the amplitude control waves of FIG. 28.

DESCRIPTION OF THE INVENTION Referring particularly to FIG. 1, room 10 has an audio source and control unit 12 and a plurality of speakers 14, 16, 18 and 20. One speaker is positioned in each corner of the room which is assumed to be generally square, with the listener assumed to be stationed in the center thereof.

The impression that sound is moving around the listener in a steady, circular fashion can be given by alternately raising and lowering the amplitude of the audio signal successively from one speaker to another at a desired rate. For example, to give the impression of sound clockwise about the room the audio signal from speaker 14 is raised to a maximum value by control waves such as 22 as shown in FIG. 2A. The audio signal for speaker 16 begins its rise in amplitude slightly behind that of the signal supplied to speaker 14, the control wave for this signal being illustrated at 24 of FIG. 2A. It will be noted that the audio signal will peak in speaker 14 and then gradually diminish while the audio signal in speaker 16 is building up to the maximum value, thus giving the impression of the sound moving from speaker 14 to speaker 16. In similarfashion the audio signals for speakers 18 and 20 are successively increased to a peak as shown by the amplitude control arrangement wherein the top row of control waves or pulses 32, 34, 36 and 38 control channel A of the four speakers, while the control waves or pulses 40, 42, 44 and 46 are for channel B of the speakers. Control waves 32, 34, 36 and 38 are respectively for speakers 1 through 4, which correspond respectively to speakers 14, 16, 18 and 20 of FIG. 1. For channel B, control wave or pulse 40 is applied simultaneously to channel B for speaker 18 while control wave 32 of channel A is applied to speaker 14. Amplitude control waves or pulses 42, 44, and 46 are respectively for speakers 4, l and 2 represented by speakers 20, 14, and 16 respectively of FIG. 1.

sound system used for the four-speaker arrangement of FIG. 1. An audio channel A source 48 and an audio channel B source 50 are shown. Channel A terminal 52 and channel B terminal 54 are connected to the rotating sound unit shown in dotted outline at 56. These channels are combined with the output from the signal generator unit 58 which has a master amplitude control signal terminal 60, an inverted master amplitude control terminal 62, a slave amplitude control wave terminal 64 and an inverted slave amplitude control wave terminal 66. The master and inverted master signals are out of phase, and referring to FIG. 2A, the master signal would be amplitude control wave 22 while amplitude control wave 26 would be the inverted master. The phase difference 30 in this example between the master amplitude control wave 22 and the slave control wave 24 is 90 but could be any desirable value.

These amplitude control waves are applied to the speaker signal circuit for each speaker such as signal circuit 68. It has a multiplier 70 for channel A and a multiplier 72 for channel B.

The audio signal from channel audio source 48 is connected through terminal 52 to the channel A multiplier input lead 74, while the master amplitude control signal from the signal generator is connected through terminal 60 through input terminal 76 of the channel A multiplier of speaker signal circuit 68. The channel B multiplier 72 of this circuit has the channel B audio supplied through channel B audio terminal 54 to the channel B input lead 78. The inverted master signal from the signal generator circuit 58 is supplied from inverted master terminal 62 through the channel B amplitude control input lead to multiplier 72.

The output from channel A multiplier 70 and channel B multiplier 72 are fed to the adder 82 and subsequently through an amplifier 84 to speaker 86. Speaker 86 would correspond to speaker No. l or speaker 14 of FIG. 1.

Speaker 88 which would correspond to speaker No. 2 or speaker 16 of FIG. 1 is supplied with its channel A audio signal through the channel multiplier 90 which has its audio input lead 94 connected directly to the channel A audio output terminal 52. The amplitude control input lead 96 is connected to the slave amplitude control wave output terminal 64. The channel B multiplier 92 has its channel B audio input lead 98 connected to the channel B audio outputv terminal 54, and the amplitude control wave' input lead 100 is connected to the inverted slave output terminal 66 of the amplitude control wave generator circuit 58.

Similarly, channel A multiplier 104 and channel B multiplier 106 receive the channel A and B signals and their corresponding amplitude control waves from the signal generator circuit 58 for speaker 108 which represents speaker No. 3.or speaker 18 of FIG. 1. Multiplier units 110 and 112 perform the same function for speaker 114 which represents speaker No. 4 and speaker No. 20 of FIG. 1.

FIG. 4 is the block diagram for the circuit used to produce the master and inverted master amplitude control signals in the signal generator circuit 58 of FIG. 3. A flip-flop circuit 116 sends a control signal through a buffer amplifier 118 and then through an integrator 120 from where it is passed to an inverter circuit 122. A comparator circuit 124 has a control voltage terminal126 with an input voltage of 5.6. The output signal is passed back to the flip-flop circuit 116. Lower voltage comparator 128 has a 1.2 voltage input terminal 130 with its output connected to the flip-flop circuit 116. The master amplitude control signal terminal 132 is connected to the output of the integrator 120. The inverted master amplitude control signal terminal 13 is obtained from the inverter 122.

In FIG. a block diagram of the circuitry used to obtain the slave and inverted slave amplitude control waves is shown. The comparator circuit 136 receives the master amplitude control wave at the input terminal 138, and has a reference voltage terminal 140 maintained at 3.4 volts. Signals from the comparator are applied through a buffer stage 142 to the holder circuits 144 and 146. The signals passed through these units are supplied to an integrator circuit 148 which produces the slave amplitude control wave. The control wave is taken through the slave amplitude control wave terminal 150. The output from the integrator 148 is fed to the inverter 152 and its output is tapped at the inverted slave amplitude control wave terminal 154. The upper and lower voltage limit comparator circuits are shown at 156 and 158.

The detailed circuitry of FIG. 4 is shown in FIG. 6. The flip-flop circuit section is illustrated at 160. The input voltage lines 162 and 164 supply the control voltage signals to this circuit. The upper voltage limit comparator circuit 166 has a reference voltage of 5.6 and is connected to input lead 162. The lower voltage comparator circuit 168 has a reference voltage of 1.2 volts and supplies its output signal to the flip-flop circuit along line 164.

The output from the flip-flop circuit is applied to the buffer stage 170 and its output is supplied directly to the integrator circuit 172 through a multi-element switch unit 174, the output of which is directly connected to the differential amplifier 176. The master amplitude control signal is obtained at output terminal 178. The output signal from the differential amplifier is directly fed to the inverter stage and the out-put from the collector of this stage is the inverted master amplitude control wave, which is tapped at this point through the inverted master terminal.

The desired reference voltages are obtained in the reference voltage circuitv 182 where terminal 184 supplies the higher limit of voltage of 5.6 volts, and terminal 186 supplies the lower reference voltage of 1.2 volts.

In FIG. 7 the triangularly shaped amplitude control waves for the master signal, inverted master, slave, and inverted slave waves produced by the signal generator circuit 58 of FIG. 3 and as further illustrated in FIGS. 4, 5 and 6 are shown. The circuitry of FIG. 6 produces the master'and inverted master amplitude control signals illustrated in FIG.'7, the waves are identical except for a DC. potential difference and are 180 out of phase.

The slave signal generating circuit illustrated in block diagram in FIG. 5 shows a comparator circuit 136 which has the same circuitry configuration of the 5.6 volt buffer section 166 of FIG. 6. The buffer circuit 170 of FIG. 6 is also used at the buffer stage 142 in the slave circuit shown in FIG. 5. The integrator circuit 172 of FIG. 6 using a differential amplifier is also used in the integrator circuit 148 of FIG. 5 for generating the slave signal. The inverter section 180 of FIG. 6 is used as the inverter circuitry generally designated 152 in FIG. 5 to produce the inverted slave signal.

The 5 .6 volt and L2 volt comparator circuits in both the slave and the master amplitude control wave generating circuits are the same. The slave comparator circuit 136 has a master amplitude control signal applied at one input, while a potentiometer connected between the 5.6 upper volt level and the 1.2 volt lower level supplies the second input to the comparator circuit.

FIG. 8 shows the circuitry of the multipliers such as 70 and 72 of FIG. 3. The master or slave signal is supplied to the input terminal 190 passing through the resistance 192 to the base of transistor 194. The audio input is supplied through terminal 196 to the transistor 198.

The amplitude of the signal is governed by the potentiometer value 200 and the governing transistor 202,

the emitter of which is connected to the B-minus terminal through a resistor. The emitter of transistor 194 is connected to the negative terminal through resistor 204 through which the low frequency to the multiplier is governed. I

Positive voltage is' applied to the circuit through the B-plus terminal 206. The output passes through capacitor 208 to the output terminal 210 where the signal is then passed to the adder unit of the speaker signal circuit 68 such as shown in FIG. 3.

The adder circuit such as that which could be used at 82 of FIG. 3 is shown in FIG. 9. The input terminal 212 receives the signal from the output of the multiplier 70 while the input terminal 214 of FIG. 9 would receive the output of multiplier 72. The two signals are merged and supplied to the differential amplifier 216 through the' lead 218. The amplifier is connected to ground through the bias lead 220. Bypass circuit 222 is connected with the output 224 which supplies the signal through an amplifier to the speaker unit.

FIG. illustrates a circuit wherein a square amplitude control wave is generated in place of the triangular control wave described previously. The square control wave timing diagrams are shown in FIG. 2B. A potentiometer 226 controls the amount of voltage supplied to the emitter of the unijunction transistor 228. The output of the transistor passes along line 230 to master clock 232 which is a J-K, master-slave flip-flop which is wired into an inverting mode. The output is passed along the common block pulse line 234 to the first or master clock 236. The output of the master pulse is tapped at a master pulse terminal 238, while the signal is passed along the output line 240 to the next stage.

A lighting circuit is activated by the output which is passed along line 242 and through the transistor 244 to the light 246. l i

i The second succeeding pulse or slave pulse is generated by the second shift register unit 248, the output of which passes along line 250 to the next shift register and to the slave signal pulse output terminal 252. Line 254 supplies the current for activating the corresponding slave light 256.

The succeeding pulse is generated by the third shift register or clock 258 which acts as the inverted master pulse generating unit. The pulse output is passed along output line 260 to the next succeeding clock unit and also to the inverted master pulse terminal 262. An indicator bulb- 264 is activated in connection with this unit.

The fmal digital clock or shift register unit 266 produces the inverted slave pulse which is passed along output line 268 to the inverted slave output terminal 270. The inverted slave shift register has a corresponding indicator light 272 which functions in the same manner as the previously mentioned indicator lights.

ln the units, 236, 248, 258 and 266 are synchronously reset by the simple switch disposed below the master clock unit 232, and voltage states are loaded into shift registers 236, 248, 258, and 266 by momentary closure of the double pole switch 274.

The unijunction transistor clock and flip-flop and the four shift register circuit replace the signal generator block diagrams of FIGS. 4 and 5 and are used in the switching mode and are readily expanded by adding 7 more stages of flip-flops.

OPERATION Basically, the system is one in which the amplitude level of the various speakers of a multi-speaker system are accurately controlled by an electronic circuit. This is accomplished by using a signal generator circuit to produce a series of peaking amplitude control waves which are used to vary the amplitude of an audio signal supplied to a given speaker.

An amplitude control wave such as the two forms shown in FIGS. 2A and 2B are generated with a desired maximum voltage, displacement, and frequency which will give the desired efiect. Each speaker will produce an audio signal which rises and falls in accordance with the shape and frequency of the control wave applied to its particular audio-control wave mixing circuit.

For example, the volume of speaker 14 of FIG. 1 is controlled by amplitude control wave 22 of FIG. 2A to produce a steadily rising volume to a peak value and then a progressive falling off of the volume. It will be noted that as the amplitude of the control wave 22 is declining the amplitude of control wave 24 for speaker 16 is increasing and eventually becomes greater than the amplitude of control wave 22. This results in an apparent movement of sound from one speaker to the other. At the time that the amplitude in both speakers is equal the sound will appear to be originating at a point midway between both speakers. Consequently, if

a plurality of speakers are disposed to surround a lis'tening area and it is desired to give the impression of sound moving around this listening area it is only necessary to apply successive peaked audio signals to each speaker in succession to create the desired sound effect.

It will be noted that FIG. 2A shows a triangular type of control wave in which there is progressive increasing of amplitude to a peak and then steadily decreasing amplitude. This type of control wave which is generated by use of the circuit illustrated in FIGS. 4 and 6, is the most accurate type, giving the impression of a steadily moving sound from one speaker to another. However, a pulse form of control wave as illustrated in FIG. 2B could also be used.

This type of control wave, however, provides an abrupt change of amplitude from a low to a high value, and the sound will appear to abruptly move from one speaker to another.

As an example, the sound of a motorcycle applied to this circuitry would appear to move about the listener and the listening area. The circuitry provides for the speeding up or slowing down of the rotating sound by changing the frequency of the amplitude control waves. In themaster signal generator of FIG. 6 the frequency is changed by use of the multiple resistive'switch 174. The lower resistive values of the multiple resistance switch will increase the frequency of the control waves, resulting in an apparently faster speed of the motorcycle travelling about the listening area. In the slave amplitude control wave generating circuit there is a matching multiple resistive switch, and the resistor setting should be the same as that of switch 174 for a given setting.

The block diagram of FIG. 4 and the schematic of FIG. 6 illustrate the generation of the master and inverted master control waves. The initial successive pulses are generated in the flip-flop circuit which is controlled by the upper and lower voltage comparator circuits 166 and 168, respectively operational at 5.6

and 1.2 volts. The comparators set and clear the flipflop circuit, the output of which is supplied to the integrating circuit.

The slave amplitude control wave generating circuit uses a comparator rather than a flip-flop to generate control pulses, and that it is interlocked with a master circuit by reason of the master and median 3.4 volt level input to it. To minimize drift of the output voltages over a long period of time, the rise of the slave integrator circuit is slightly more than that of the master,

with the slave output being held for brief periods at the upper and lower voltage limits. This has a tendency to produce a flattened top and bottom on the slave control waves, but this is minimized by providing a slightly increased slope of the slave amplitude control waves.

The timing diagram of FIG. 7 shows the four amplitude control signals where each wave is spaced 90 apart in phase. These waves, each being combined with the audio signal, are applied to the successive speakers disposed about the listening area.

The block diagram of FIG. 3 and the circuits of FIGS. 8 and 9 illustrate the manner in which this is accomplished. I

The audio source, such as channel A source 48 is combined with the master amplitude control signal in a multiplier 70. FIG. 3 shows a two-channel system wherein channels A and B are l80 out of phase. Consequently the channel B audio unit 50 has its output connected with the inverted master wave in multiplier 72 of FIG. 3.

The multiplier circuit is shown in FIG. 8. It contains a voltage level shifting circuit comprising potentiometer 200 and transistor 202 and operates to match the multiplier voltage levels to that of the 5.6 volt and 1.2 volt upper and lower ranges of the signal generator outputs, matching those voltages to the multiplier input voltage range of 0.6 volts to volts maximum above B- minus. The shifter circuit also permits adjustment of the amplification factor in the timing diagram of FIG. 2A by adjusting the potentiometer 200. This permits a shifting of the lower voltage level. When the lower voltage level is raised the directionality of the sound source is more sharply focused. In the circuit this is accomplished through the transistor 202 where on change of the potentiometer setting the collector of the transistor becomes a current source, changing the voltage across resistor 192, and acting to control the peak current through resistor 204.

The multiplier circuit low frequency input is supplied through resistor 204, while the high frequency audio input is supplied through terminal 196 and resistor 197 to the base of transistor 198. The output capacitor 208 and the resistor 213 connected to the terminal 212 of the operational amplifier provide bypassing of audio signals only and eliminate a low frequency AC component normally present with the signal in the multiplier circuit.

FIG. 9 shows the adder unit which is an integrated circuit operational amplifier of standard configuration. It is possible to obtain a voltage gain with this circuit by choosing the desired value of the resistor in the bypass line 222.

These figures disclose a two-channel arrangement, but that is in no way limiting. It is possible to use a fourchannel system with channel A, channel 13, channel C, and channel D audio sources combined with the four amplitude control wave signals produced by the signal generator. In this instance each of the four speakers of FIG. 1 would receive through its multiplier and adder circuits, channels A through D, each channel associated with one of the amplitude control waves. There would be one adder circuit, and four multipliers of the type of FIG. 8 for each speaker. This system would be used for example for the four channel stereo units that are now coming onto the market. It can be seen that any number of channels can be rotated with the circuitry disclosed by increasing the number of multipliers to provide a mutliplier for each channel to be used, together with a corresponding voltage amplitude control a wave for that channel.

With regard to the circuit of FIG. 10 which uses the digital clock and shift register circuit to produce amplitude control waves or pulses, the multiplier circuit described immediately above, together with the conventional operational amplifier circuit can be used. However, it is also possible to use a multiplier or switch circuit for a multiplier stage wherein the audio signal is fed through a capacitor and a resistor with the output of the resistor being connected in parallel with a P- channel switching field-effect transistor through which the amplitude control pulse from the generator is supplied. The base voltage of the field-effect transistor is controlled by supplying the amplitude control waves to the base of a transistor connected across the fieldeffect transistor base and its grounded output. I

'In FIG. 10 the transistor is a unijunction unit, while all registers are .I-K, master-slave flip-flop units.

In FIG. 6 the amplifier flip-flop circuit shown in dotted outline in comparator units 166 and 168 are half of the configuration of a CA-3026 unit. The amplifier 176 used in the integrator circuit 172 is an MCl439G amplifier unit. This is-also the unit used in the integrator of the slave generating circuit. The comparators in that circuit are also CA-3026'units.

While this invention has been described in connection with the preferred embodiment, it will be understood that this invention is capable of further modification. This application is intended to cover any variations, uses, or adaptations of the invention following, as well as the principles of the invention in general including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and further including such departures as may be applied to the essential features hereinbefore set forth and fall within the scope of the invention or the limits of the appended claims.

What I claim is:

1. A multiple speaker system, comprising:

a. a plurality of speakers arranged in a preselected pattern about a listening area,

b. a common source of audio signals to be supplied to each of the speakers,

c. adjustable linear master control signal generating means for producing a recurring high to low amplitude master control wave, 7

d. linear duplicate control signal generating means for receiving the master control signal and producing a plurality of out of phase duplicate control signals, each of the signals being applied to a separate output terminal,

e. the linear duplicate control signal generating means including means for varying the phase difference between each of the duplicate control signals dependent upon the arrangement of the speakers to each other and the desired pattern of speaker actuation,

f. circuit means for varying the frequency and amplitude of the master control signal dependent upon the overall sound effect to be produced,

g. a separate variable audio signal wave producing circuit means connected to each speaker and to one of the output terminals of the linear duplicate control signal generating means for receiving and combining the common audio signal and the control signal from the output terminal for that speaker, and transmitting a systematic varying amplitude audio wave to the speaker,

h. the master control signal generating means is a shift register circuit for producing a series of successive clockpulses.

2. A multiple speaker system, comprising:

a. a plurality of speakers arranged in a preselected pattern about a listening area,

b. a common source of audio signals to be supplied to each of the speakers,

c. adjustable linear master control signal generating means for producing a recurring high to low amplitude master control wave,

d. linear duplicate control signal generating means for receiving the master control signal and producing a plurality of out of phase duplicate control signals, each of the signals being applied to a separate output terminal,

e. the linear duplicate control signal generating means including means for varying the phase difference between each of the duplicate control signals dependent upon the arrangement of the speakers to each other and the desired pattern of speaker actuation,

f. circuit means for varying the frequency and amplitude of themaster control signal dependent upon the overall sound effect to be produced,

g. a separate variableaudio signal wave producing circuit means connected to each speaker and to one of the output terminals of the linear duplicate control signal generating means for receiving and combining the common audio signal and the control signal from the output terminal for that speaker, and transmitting a systematic varying amplitude audio wave to the speaker,

h. the master signal generating means includes a pulse producing means for producing a successive train of pulses, and also includes a wave shaping circuit for receiving and modifying the shape of the train of pulses.

3. A multi-speaker sound system, comprising:

a. a plurality of loudspeaker units arranged in a preselected pattern,

b. a plurality of audio sources constituting plural audio channel signal sources,

c. a signal combining means connected between each of said speakers and one of said audio sources,

d. adjustable linea'r signal generator means for generating a succession of phase-displaced fluctuating amplitude control waves, one for each speaker,

e. means to vary the phase and amplitude of the amplitude control waves in accordance with the location of the speaker for that control wave with respect to the other speakers and the desired overall sound pattern to be created, whereby different and distinct phase-displaced amplitude varying audio signals are supplied to each of the speakers with the amplitude increasing and decreasing successively on one channel with respect to another channel to provide an impression of sound movement from speaker to speaker,

f. the signal generator means including a peaking pulse generating circuit, and circuit means for inverting the peak pulse to provide two amplitude control waves which are one hundred and eighty degrees out of phase,

g. the signal combining means including a plurality of electronic mixing circuits, and

h. an operational amplifier is connected between the outputs of several of the mixing circuits and the input to their. corresponding loud speaker.

4. A multiple speaker system, comprising:

a. a plurality of speakers arranged in a preselected pattern about a listening area,

b. a common source of audio signals to be supplied to each of the speakers,

c. adjustable linear master control signal generating means for producing a recurring high to low amplitude master control wave,

d. linear duplicate control signal generating means for receiving the master control signal and producing a plurality of out of phase duplicate control signals, each of the signals being applied to a separate output terminal,

e. the linear duplicate control signal generating means including means for varying the phase difference between each of the duplicate control signals dependent upon the arrangement of the speakers to each other and the desired pattern of speaker actuation,

f. circuit means for varying the frequency and amplitude of the master control signal dependent upon the overall sound effect to be produced,

g. a separate variable audio signal wave producing circuit means connected to each speaker and to one of the output terminals of the linear duplicate control signal generating means for receiving and combining the common audio signal and the control signal from the output terminal for that speaker, and transmitting a systematic varying amplitude audio wave to the speaker,

h. said circuit means for varying the frequency and amplitude of the master control signal including means for shifting the lower voltage level of the control signal for more sharply focusing the directionality of the sound source.

5. A multi-speaker sound system, comprising:

a. a plurality of loudspeaker units arranged in a preselected pattern,

b. a plurality of audio sources constituting plural audio channel signal sources,

0. a signal combining means connected between each of said speakers and one of said audio sources,

d. adjustable linear signal generator means for generating a succession of phase-displaced fluctuating amplitude control waves, one for each speaker,

e. means to vary the phase and amplitude of the amplitude control waves in accordance with the location of the speaker for that control wave with respect to the other speakers and the desired overall sound pattern to be created, whereby different and distinct phase-displaced amplitude varying audio signals are supplied to each of the speakers with the amplitude increasing and decreasing successively on one channel with respect to another channel to provide an impression of sound movement from speaker to speaker,

f. the signal generator means including a peaking pulse generating circuit, and circuit means for inverting the peak pulse to provide two amplitude control waves which are 180 out of phase, and

g. said generator means also including means for shifting the lower voltage level of the control signals for more sharply focusing the directionality of the sound source.

6. A variable amplitude speaker system comprising:

a. an audio source,

b. a loudspeaker unit,

c. combining circuit means connected between the source and the speaker to receive the audio signal from the source and to receive a variable amplitude control signal for combining both signals for producing a variable amplitude audio signal which is passed on to the loudspeaker,

d. a signal generating circuit for generating the variable amplitude control signal which includes a flipflop circuit controlled by a high voltage and a low voltage comparator, and

e. the signal generator circuit also includes integrator means for receiving pulses from the flip-flop circuit and shaping them to form a peaked amplitude control wave, the output of the integrator circuit being connected to the signal combining circuit to supply the variable amplitude control signal thereto.

7. The variable amplitude speaker system as set forth in claim 6, wherein:

a. the signal generator circuit means also includes a secondpulse train generating circuit connected to the flip-flop circuit and controlled by the output thereof, the second circuit also including an integrator circuit means for receiving the pulse output from the second pulse generating circuit and shaping it to form a peaked continuous amplitude control wave.

8. The variable amplitude speaker system as set forth in claim 6, wherein:

a. variable resistance control means is connected to the flip-flop circuit for varying the frequency of its change of state.

9. A multi-channel variable amplitude speaker system, comprising:

a. a two-channel audio source,

b. periodic peaking voltage generator circuit means for producing two-phase displaced amplitude control of voltages,

c. a first multiplier circuit having one of its input lines connected to one of the two audio channels and its other input connected to the output of the voltage generator to receive one of the two-phasedisplaced amplitude control waves,

d. a second multiplier having one of its input lines connected to the other of the two audio channel sources and its second input line connected to the output of the voltage generator to receive the second of the phase-displaced amplitude control waves,

e. an adder circuit connected to the output of each of the multipliers and having its output connected to a loudspeaker to produce an amplitude controlled audio signal, the amplitude of which is governed by the amplitude control waves supplied by the voltage generator.

10. The multi-channel variable amplitude speaker system as set forth in claim 9, wherein:

a. the voltage generator circuit means is a clocking circuit which produces a plurality of pulses. 11. The multi-channel variable amplitude speaker system of claim 9, wherein:

a. the voltage generator circuit means includes a periodic pulse producing circuit and a pulse shaping circuit which receives the periodic pulses and changes their shape to produce a succession of peaking amplitude control pulses.

12. The multi-channel variable amplitude speaker system of claim 9, wherein:

system of claim 9, wherein:

a. the adder is a conventionally wired operational amplifier which is AC coupled to the output of the multipliers.

14. The multiple speaker system of claim 1, wherein:

a. the variable audio signal wave producing circuit means includes a multiplier circuit means for each speaker for combining an amplitude control wave with a single audio signal.

15. The multiple speaker system of claim 1, wherein:

a. the audio source includes plural audio channel sources to provide plural channel sound, and

b. the master control signal generating means provides amplitude control waves for each channel.

16. The multiple speaker system of claim 1, wherein:

a. said pulse producing means is a flip-flop circuit,

and

b. the wave shaping circuit is an integrating circuit.

17. The multiple speaker circuit of claim 16,

wherein:

curt.

* n s s s 

1. A multiple speaker system, comprising: a. a plurality of speakers arranged in a preselected pattern about a listening area, b. a common source of audio signals to be supplied to each of the speakers, c. adjustable linear master control signal generating means for producing a recurring high to low amplitude master control wave, d. linear duplicate control signal generating means for receiving the master control signal and producing a plurality of out of phase duplicate control signals, each of the signals being applied to a separate output terminal, e. the linear duplicate control signal gEnerating means including means for varying the phase difference between each of the duplicate control signals dependent upon the arrangement of the speakers to each other and the desired pattern of speaker actuation, f. circuit means for varying the frequency and amplitude of the master control signal dependent upon the overall sound effect to be produced, g. a separate variable audio signal wave producing circuit means connected to each speaker and to one of the output terminals of the linear duplicate control signal generating means for receiving and combining the common audio signal and the control signal from the output terminal for that speaker, and transmitting a systematic varying amplitude audio wave to the speaker, h. the master control signal generating means is a shift register circuit for producing a series of successive clockpulses.
 2. A multiple speaker system, comprising: a. a plurality of speakers arranged in a preselected pattern about a listening area, b. a common source of audio signals to be supplied to each of the speakers, c. adjustable linear master control signal generating means for producing a recurring high to low amplitude master control wave, d. linear duplicate control signal generating means for receiving the master control signal and producing a plurality of out of phase duplicate control signals, each of the signals being applied to a separate output terminal, e. the linear duplicate control signal generating means including means for varying the phase difference between each of the duplicate control signals dependent upon the arrangement of the speakers to each other and the desired pattern of speaker actuation, f. circuit means for varying the frequency and amplitude of the master control signal dependent upon the overall sound effect to be produced, g. a separate variable audio signal wave producing circuit means connected to each speaker and to one of the output terminals of the linear duplicate control signal generating means for receiving and combining the common audio signal and the control signal from the output terminal for that speaker, and transmitting a systematic varying amplitude audio wave to the speaker, h. the master signal generating means includes a pulse producing means for producing a successive train of pulses, and also includes a wave shaping circuit for receiving and modifying the shape of the train of pulses.
 3. A multi-speaker sound system, comprising: a. a plurality of loudspeaker units arranged in a preselected pattern, b. a plurality of audio sources constituting plural audio channel signal sources, c. a signal combining means connected between each of said speakers and one of said audio sources, d. adjustable linear signal generator means for generating a succession of phase-displaced fluctuating amplitude control waves, one for each speaker, e. means to vary the phase and amplitude of the amplitude control waves in accordance with the location of the speaker for that control wave with respect to the other speakers and the desired overall sound pattern to be created, whereby different and distinct phase-displaced amplitude varying audio signals are supplied to each of the speakers with the amplitude increasing and decreasing successively on one channel with respect to another channel to provide an impression of sound movement from speaker to speaker, f. the signal generator means including a peaking pulse generating circuit, and circuit means for inverting the peak pulse to provide two amplitude control waves which are one hundred and eighty degrees out of phase, g. the signal combining means including a plurality of electronic mixing circuits, and h. an operational amplifier is connected between the outputs of several of the mixing circuits and the input to their corresponding loud speaker.
 4. A multiple speaker system, comprising: a. a plurality of speakers arranged in a preselected pattern about a listEning area, b. a common source of audio signals to be supplied to each of the speakers, c. adjustable linear master control signal generating means for producing a recurring high to low amplitude master control wave, d. linear duplicate control signal generating means for receiving the master control signal and producing a plurality of out of phase duplicate control signals, each of the signals being applied to a separate output terminal, e. the linear duplicate control signal generating means including means for varying the phase difference between each of the duplicate control signals dependent upon the arrangement of the speakers to each other and the desired pattern of speaker actuation, f. circuit means for varying the frequency and amplitude of the master control signal dependent upon the overall sound effect to be produced, g. a separate variable audio signal wave producing circuit means connected to each speaker and to one of the output terminals of the linear duplicate control signal generating means for receiving and combining the common audio signal and the control signal from the output terminal for that speaker, and transmitting a systematic varying amplitude audio wave to the speaker, h. said circuit means for varying the frequency and amplitude of the master control signal including means for shifting the lower voltage level of the control signal for more sharply focusing the directionality of the sound source.
 5. A multi-speaker sound system, comprising: a. a plurality of loudspeaker units arranged in a preselected pattern, b. a plurality of audio sources constituting plural audio channel signal sources, c. a signal combining means connected between each of said speakers and one of said audio sources, d. adjustable linear signal generator means for generating a succession of phase-displaced fluctuating amplitude control waves, one for each speaker, e. means to vary the phase and amplitude of the amplitude control waves in accordance with the location of the speaker for that control wave with respect to the other speakers and the desired overall sound pattern to be created, whereby different and distinct phase-displaced amplitude varying audio signals are supplied to each of the speakers with the amplitude increasing and decreasing successively on one channel with respect to another channel to provide an impression of sound movement from speaker to speaker, f. the signal generator means including a peaking pulse generating circuit, and circuit means for inverting the peak pulse to provide two amplitude control waves which are 180* out of phase, and g. said generator means also including means for shifting the lower voltage level of the control signals for more sharply focusing the directionality of the sound source.
 6. A variable amplitude speaker system comprising: a. an audio source, b. a loudspeaker unit, c. combining circuit means connected between the source and the speaker to receive the audio signal from the source and to receive a variable amplitude control signal for combining both signals for producing a variable amplitude audio signal which is passed on to the loudspeaker, d. a signal generating circuit for generating the variable amplitude control signal which includes a flip-flop circuit controlled by a high voltage and a low voltage comparator, and e. the signal generator circuit also includes integrator means for receiving pulses from the flip-flop circuit and shaping them to form a peaked amplitude control wave, the output of the integrator circuit being connected to the signal combining circuit to supply the variable amplitude control signal thereto.
 7. The variable amplitude speaker system as set forth in claim 6, wherein: a. the signal generator circuit means also includes a second pulse train generating circuit connected to the flip-flop circuit and controlled by the output thereof, the second circuit also including an intEgrator circuit means for receiving the pulse output from the second pulse generating circuit and shaping it to form a peaked continuous amplitude control wave.
 8. The variable amplitude speaker system as set forth in claim 6, wherein: a. variable resistance control means is connected to the flip-flop circuit for varying the frequency of its change of state.
 9. A multi-channel variable amplitude speaker system, comprising: a. a two-channel audio source, b. periodic peaking voltage generator circuit means for producing two-phase displaced amplitude control of voltages, c. a first multiplier circuit having one of its input lines connected to one of the two audio channels and its other input connected to the output of the voltage generator to receive one of the two-phase-displaced amplitude control waves, d. a second multiplier having one of its input lines connected to the other of the two audio channel sources and its second input line connected to the output of the voltage generator to receive the second of the phase-displaced amplitude control waves, e. an adder circuit connected to the output of each of the multipliers and having its output connected to a loudspeaker to produce an amplitude controlled audio signal, the amplitude of which is governed by the amplitude control waves supplied by the voltage generator.
 10. The multi-channel variable amplitude speaker system as set forth in claim 9, wherein: a. the voltage generator circuit means is a clocking circuit which produces a plurality of pulses.
 11. The multi-channel variable amplitude speaker system of claim 9, wherein: a. the voltage generator circuit means includes a periodic pulse producing circuit and a pulse shaping circuit which receives the periodic pulses and changes their shape to produce a succession of peaking amplitude control pulses.
 12. The multi-channel variable amplitude speaker system of claim 9, wherein: a. each of the multiplier circuits includes a level shifter circuit connected between the signal voltage generator circuit means and the amplitude control wave input lead to the multiplier for controlling the directivity of the sound impression by shifting the zero level of the amplitude control wave.
 13. The multi-channel variable amplitude speaker system of claim 9, wherein: a. the adder is a conventionally wired operational amplifier which is AC coupled to the output of the multipliers.
 14. The multiple speaker system of claim 1, wherein: a. the variable audio signal wave producing circuit means includes a multiplier circuit means for each speaker for combining an amplitude control wave with a single audio signal.
 15. The multiple speaker system of claim 1, wherein: a. the audio source includes plural audio channel sources to provide plural channel sound, and b. the master control signal generating means provides amplitude control waves for each channel.
 16. The multiple speaker system of claim 1, wherein: a. said pulse producing means is a flip-flop circuit, and b. the wave shaping circuit is an integrating circuit.
 17. The multiple speaker circuit of claim 16, wherein: a. the integrating circuit is a differential amplifier circuit. 